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Three-cylinder Marine Engines.

685

valves s, and delivery valves R to prevent the water returning.
The bucket is actuated by the bell-crank lever ww, connected by
links to the crosshead x. The connecting rod e has a long fork
to clear the pump barrel; it is also light in construction, its sole
duty being to transmit equalising energy to or from the fly wheel,
in addition to the power required to work the valves. The pump
suction pipe is at d d, and the delivery pipe at bb, but full ex-
planation will be left to the next chapter. We must not omit
to mention the hydraulic governor g, the invention of Mr.
C. R. Parkes, M.I.C.E., which has given great satisfaction in
its working. The flying balls are driven from the engine in
the usual manner, but the sleeve opens a small D valve to
hydraulic pressure or exhaust, according to whether it rises or falls.
Nothing takes place until the governor has attained a speed of
15 revolutions per minute, when high-pressure water is admitted
into the cylinder /£, and the ram / is pushed downward, thus also
pulling down the strap k and raising the weight /. The conse-
quence is that the pulley f, on the expansion valve spindle, is
rotated so as to increase the lap of the Meyer valve and secure an
earlier cut-off, and the action will continue until the speed of the
•engine has returned to the normal, when the governor sleeve will
fall, open the D valve to exhaust, and allow the weight / to lift
ram j to its original position,

Triple Expansion Marine Engines.—Figs. 666 and
£67, Plate XVII., are two views of the triple-expansion engines of
the Pacific steamer Iberia, designed and constructed by Messrs.
David Rollo and Sons, of Liverpool. The bed plate y, in three
pieces, carries the left-hand standards; the right-hand standards K,
KJ, and Kn, being built upon the condenser v. Cylinders.—The
H. P. cylinder A is 33 ins. diameter, B the intermediate is 54 ins.,
" and c the L. P. cylinder is 88 ins.; while G, H, and j are the
respective pistons, of conical form to combine lightness with
strength, and each having a stroke of 60 ins. To minimise the
number of spare parts, the cranks YVY, connecting rods zzz, piston
rods DBF, eccentric s and rods STU, links r, gudgeons zz, crossheads #, •
and pump levers jk, are all made respectively interchangeable;
only a small alteration occurring with the rod D, which must have
the tail or upper part cut off. Valves.—A piston valve b is